[PATCH net-next 1/1] net: phy: marvell10g: Add PHY loopback support for 88E2110 PHY

[Wong Vee Khee <vee.khee.wong@linux.intel.com>]

From: Tan Tee Min <tee.min.tan@intel.com>

Add support for PHY loopback for the Marvell 88E2110 PHY.

This allow user to perform selftest using ethtool.

Signed-off-by: Tan Tee Min <tee.min.tan@intel.com>
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
---
 drivers/net/phy/marvell10g.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/phy/marvell10g.c b/drivers/net/phy/marvell10g.c
index b1bb9b8e1e4e..c45a8f11bdcf 100644
--- a/drivers/net/phy/marvell10g.c
+++ b/drivers/net/phy/marvell10g.c
@@ -89,6 +89,8 @@ enum {
 	MV_V2_TEMP_CTRL_DISABLE	= 0xc000,
 	MV_V2_TEMP		= 0xf08c,
 	MV_V2_TEMP_UNKNOWN	= 0x9600, /* unknown function */
+
+	MV_LOOPBACK		= BIT(14), /* Loopback (88E2110 only) */
 };
 
 struct mv3310_priv {
@@ -765,6 +767,15 @@ static int mv3310_set_tunable(struct phy_device *phydev,
 	}
 }
 
+static int mv3310_loopback(struct phy_device *phydev, bool enable)
+{
+	if (phydev->drv->phy_id != MARVELL_PHY_ID_88E2110)
+		return -EOPNOTSUPP;
+
+	return phy_modify_mmd(phydev, MDIO_MMD_PCS, MV_PCS_BASE_T,
+			      MV_LOOPBACK, enable ? MV_LOOPBACK : 0);
+}
+
 static struct phy_driver mv3310_drivers[] = {
 	{
 		.phy_id		= MARVELL_PHY_ID_88X3310,
@@ -796,6 +807,7 @@ static struct phy_driver mv3310_drivers[] = {
 		.get_tunable	= mv3310_get_tunable,
 		.set_tunable	= mv3310_set_tunable,
 		.remove		= mv3310_remove,
+		.set_loopback	= mv3310_loopback,
 	},
 };
 
-- 
2.25.1